1. Field of the Invention
The present invention relates to a method of producing a cracker or the like from a raw material such as grain such as unhulled rice or the like, or artificial rice, starch or the like mixed with desired raw materials such as cheese, tiny fish, shrimp, vegetable or the like and formed in a chip-shape. The invention also relates to an apparatus for carrying out the method.
2. Description of the Prior art
Heretofore, cracker-type foods produced from such raw materials as rice, soybean, corn or the like have been liked by many people as nourishing natural foods. In the known method for producing this type of foods, a raw material already processed in advance to have a predetermined water content is fed into heated and air-tight chamber defined in upper and lower baking molds, compressed and heated therein. Thereafter, upon lapse of a predetermined time, the upper or the lower baking mold is vertically moved to remove the compression. As a result, the raw material is caused to expand instantaneously to form a cracker of a self-sustaining structure.
In the known method set forth above, vertical movement of the upper and lower baking molds, or sliding movement of a slide plate for feeding the raw material into the lower baking mold is performed by actuation of an air cylinder. However, employment of the air cylinder has the disadvantage that even a slight change of air quantity fed from a compressor delicately changes the movement of, inter alia, the upper and the lower baking molds, resulting in too large or too small compression on the raw material. As a result, baking conditions for the raw material are changed. In addition, due to change of removing speed of the compression, etc., the thickness of the expanded crackers cannot be made uniformly, which badly spoils a production value thereof. Furthermore, actuation of the air cylinder requires installation of a compressor. Accordingly, an assembly of such apparatus as a whole is required to be made large. Moreover, structure thereof becomes complicated due to arrangement of electric circuits, installation of various kinds of valves, connection of air hoses, etc. The complicated structure often brings about mechanical troubles. A consideration is also made to employ a hydraulic cylinder instead of the air cylinder. However, the hydraulic cylinder assembly itself is bulky and expensive. Besides, the hydraulic cylinder possesses such fundamental disadvantages as that it cannot reverse the direction of movement while it is in the process of advancing or retreating movement, nor can it advance or retreat instantaneously. Accordingly, the hydraulic cylinder is not desirable for practical use for a cracker producing apparatus, in which delicate actuation and movement of component parts thereof are required.
The present invention has been accomplished in order to solve the above mentioned problems inherent in the prior art.